Drainage catheters are generally used to drain bile or pus from a body cavity, for example, an abdominal cavity in order to mitigate symptoms of diseases. A Drainage catheter comprises a tubular member having a proximal end opposite a distal end, a tension member, and a lockable connector. The tubular member includes a series of holes positioned proximate the distal end. The distal end of the tubular member is formed to be positioned into a desired configuration such as a closed loop or pigtail. The tension member extends through the hollow tubular member and is positioned for drawing the distal end into the desired configuration. The lockable connector comprises a hub coupled to the proximal end of the tubular member and a locking lever coupled to the hub. The locking lever secures the pulling end of the tension member to the hub after the tension member is fully pulled so that the desired loop configuration can be maintained. The hub has a coupling end, through which a channel extends. The channel is aligned with and connected to the tubular member by a connector cap.
FIG. 1 shows a cam-locked drainage catheter, as a conventional drainage catheter, which can adjust arbitrarily a loop configuration of a distal end (10′) of a tubular member (1′). The cam-locked drainage catheter comprises a lockable connector (2′) having a hub and a locking lever (21′) pivotedly connected in a channel of the hub for moving a cam surface at one end of the lever between a locked position and an unlocked position. Thus, a patient can easily use the drainage catheter with one hand. These catheters are typically introduced into the patient by means of a large hypodermic needle or trocar. A wire guide is inserted through the needle, which is then removed. The tubular member (1′) with a stiffening cannula positioned therein is then passed over the wire guide into a body cavity. The cannula and wire guide are withdrawn, leaving the catheter in the desired cavity. Then, a proximal end of a monofilament (4′) as a tension member is moved or drawn to form the distal end (10′) into a desired loop or pigtail configuration. Next, the locking lever (21′) is pulled downward to fix the position of the monofilament with respect to the tubular member, thereby maintaining the desired loop configuration. Here, the protruding end of the monofilament (4′) may be cut so as to get an appropriate length. When the locking lever (21′) is pulled upward, the lever rotates by appropriate angles and the monofilament is released automatically from the locking lever (21′), thereby releasing the pigtail configuration. In addition, the loop configuration of the flexible distal end can be reformed into another configuration after straightening the distal end portion by inserting the stiffening cannula into the catheter tube.
The conventional cam-locked drainage catheters have the pivotable locking lever to hold the monofilament in place so that the loop configuration is maintained through its intended use, and, therefore, doctors can easily lock or unlock the lockable connector (2′) of the catheter. However, the lever (21′) may be rotated arbitrarily due to movement of a patient or inadvertences during operation, and, therefore, the monofilament may move distally and release the pigtail configuration. In addition, because a tip of the catheter tube is made of flexible (or soft) material such as polyamide, it is difficult to insert the catheter tube into a blood vessel.